Nonvolatile memory, such as NAND or NOR based flash memory, is widely used in today's technology world. Its unique cell and array structures provide small cell size, high density, low write current, and high throughout. Nonvolatile memory such as NAND based flash memory becomes major storage memory for various devices and systems, such as memory cards, USB flash drives, and solid-state drives. Some exemplary applications of flash memory include personal computers, PDAs, digital audio players, digital cameras, mobile phones, synthesizers, video games, scientific instrumentation, industrial robotics, and medical electronics.
With recent development of semiconductor processing technology, the transformation from two-dimensional (“2D”) to three-dimensional (“3D”) NAND flash memory becomes possible. A 3D NAND flash memory, for example, can reach 128 to 256 gigabit (“Gb”) storage capacity. Although conventional 3D NAND flash memory technology, for example, may use 16 nanometers (“nm”) technology, the typical speed for NAND flash memory is relatively slow in comparison with the speed for dynamic random-access memory (“DRAM”) or static random-access memory (“SRAM”).
A problem, however, associated with a typical 3D NAND based flash memory is data transfer between nonvolatile memory (“NVM”) chip and random-access memory chip such as DRAM and/or SRAM. Since the conventional NVM and DRAM are fabricated in different dies, communication between NVM and DRAM via an external bus(s) typically hampers overall data transfer speed.
Another drawback associated with conventional NAND based flash memory is that it has a relatively slow programming speed. A reason for a slow programming speed and/or erasing speed is that a conventional NAND flash memory performs single-page programming. For some applications, a slow programming and/or erasing speed in a nonvolatile memory storage becomes a limitation.